Preparation for treating washed laundry in a tumble dryer

ABSTRACT

An article for treating washed laundry in a tumble dryer to provide the laundry with a pleasant, soft and full feel, and antistatic properties. The article is a flexible sheet-form substrate coated with a mixture of (a) a fatty component selected from a fatty acid mono-, di-, and tri-glyceride, a fatty acid and a fatty alcohol, and (b) a fatty acid ester of a monohydric alcohol.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a preparation for treating washed laundry in atumble dryer consisting of a flexible sheet-form material coated with amixture of active substances for treating laundry.

With the development of automatic tumble dryers, in which washed laundryis dried by heated air, it became possible to carry out the treatment oflaundry generally effected during the final rinse cycle of a washingmachine in a tumble dryer. The object of treating washed laundry in thisway is generally to give the laundry a pleasant soft and full feel,anti-electrostatic properties and an agreeable fragrance. Whereas, inthe treatment of laundry in the final rinse cycle, it had always beennecessary to use active substances which were completely transferred tothe fabrics to be treated in the aqueous wash liquor, the shift of thetreatment process to a tumble dryer made it possible to use activesubstances that were difficult or even impossible to use in aqueous washliquors. Although, in principle, active substances different from thoseused in the final rinse cycle can be used in the treatment of laundry ina tumble dryer, the active substances used in the final rinse treatment,namely quaternary ammonium compounds containing 1, 2 or 3 long groups inthe molecule derived from ammonia or imidazoline, have hitherto alsobeen used almost exclusively in the treatment of laundry in a tumbledryer. The reason for this is that quaternary ammonium compounds such asthese can be synthesized relatively easily and, above all, are extremelyeffective as fabric softeners.

2. Discussion of Related Art

Various proposals have been put forward for the application of fabricsofteners to fabrics in a tumble dryer. For example, it has beenproposed to transfer the active substances to the laundry, if desiredtogether with additional auxiliaries, from rigid containers added to thelaundry in the tumble dryer. In addition to rigid containers, flexiblecontainers, for example bags, filled with the active substances havealso been proposed. However, the most simple and, hence, generally themost common option is the release of the active substances from flexiblesheet-form materials. The treatment of laundry in a tumble dryer byflexible sheet-form materials impregnated with active substances isdescribed, for example, in German patent application DE-A 19 55 803.However, depending on the type of sheet-form textile used forimpregnation with the active substance, the problem arises that, in thecase of substrates having a low adsorption capacity, the fatty activesubstances are unevenly transferred to the fabrics and leave greasymarks thereon. Other substrate materials of high adsorption capacity,such as for example sponge cloths or foam sheets, do not provide for anadequate release of the active substances so that, where they are usedas carriers for the active substances, losses of active substances areincurred in the form of unused active substances.

According to the teaching of DE-A 19 65 470, the disadvantages describedabove can be overcome by using substrates of medium adsorption capacityas carriers for the quaternary ammonium compounds. However, it wassubsequently found that, under certain conditions, it is even possibleto use substrates of low adsorption capacity, which have the advantageof high active-substance release, without any marks being left on thelaundry. Preparations for the treatment of washed laundry in a tumbledryer, of which the carriers for the fabric softeners include asubstrate of low adsorption capacity, are the subject of DE-A 30 03 249.

According to the teaching of DE-A 27 00 512,up to 60% of the softeningquaternary ammonium compounds can be replaced by fatty acid esters of apolyhydric alcohol. This has the advantage that the substrates used ascarriers for the fabric softeners are not required to have a specificadsorption capacity.

Laundry treatment preparations for use in tumble dryers, of which theactive substances are free from quaternary ammonium compounds, are alsoknown. For example, DE-A 25 16 104 describes products of which theactive component consists completely or partly of sorbitan esters.However, in the same way as the quaternary ammonium compounds, sorbitanesters cause staining or are characterized by an inadequate release ofactive substance unless materials of medium adsorption capacity are usedas the substrate.

Other fabric softening agents which do not contain any quaternaryammonium compounds are the fatty acid esters of polyhydric alcoholsknown, for example, from DE 27 00 512. According to the teaching of thispatent application, however, they have to be used in conjunction withappreciable quantities (40 to 95% by weight) of cationic fabricsofteners of the quaternary ammonium compound type. However, it hasrecently been found that, on account of their more or less pronouncedtoxic properties and their poor biodegradability, quaternary ammoniumcompounds pollute the wastewater which they enter on completion of therinse cycle or together with the wash liquor of the washing processfollowing the aftertreatment. Accordingly, the problem addressed by thepresent invention was to provide fabric-softening mixtures for thetreatment of washed laundry in a tumble dryer, the mixtures beingreleased and transferred to the fabrics to be treated without stainingand at a high rate from a flexible sheet-form material serving ascarrier for the active substances and the mixtures being free fromquaternary ammonium compounds. Another problem addressed by theinvention was to provide a fabric softener or mixture of fabricsofteners which, in the production process, would solidify rapidly, i.e.at a relatively high temperature, after application to the flexiblesheet-form material to form a layer with a dry feel and would providethe fabrics thus treated with good anti-electrostatic properties.

DESCRIPTION OF THE INVENTION

It has now surprisingly been found that fatty acid glycerides, which areunsuitable on their own as fabric softeners, can be combined with otherfatty alcohol or fatty acid derivatives, likewise unsuitable on theirown as fabric softeners, to form mixtures which do not have any of theabove-mentioned disadvantages of known mixtures and which meet the otherrequirements mentioned.

Accordingly, the present invention relates to preparations for thetreatment of washed laundry in a tumble dryer consisting of a flexiblesheet-form material coated with mixtures of active substances for thetreatment of laundry, the mixtures containing a fatty component,characterized in that the fatty component a) comprising fatty acidmono-, di- or triglycerides and/or fatty acids and/or fatty alcohols ispresent in admixture with b) fatty alcohol alkoxylates and/or fatty acidesters of monohydric alcohols.

The constituents of the fatty component a) are known individually asfabric softeners, but on their own or even in combination with oneanother do not meet the requirements defined in detail in thedescription of the problem addressed by the invention. Thus, they areeither difficult to process because they solidify too slowly or tooquickly after application to the flexible sheet-form material; or theydo not provide the fabrics thus treated with adequate softness orsatisfactory anti-electrostatic properties; or the flexible sheet-formmaterials coated with them have an unpleasant feel which discourages theconsumer from using them; or the active-substance release rate is toolow. Accordingly, the fatty component a) is combined with a component b)consisting of fatty alcohol alkoxylates and/or fatty acid esters ofmonohydric alcohols in such a way that the active-substance mixturesformed begin to crystallize at a temperature of 40° C. or higher. In thecontext of the present patent application, the beginning ofcrystallization is determined by DSC measurement with a Mettler FP 84differential scanning calorimeter. The mixture of active substances tobe tested is heated at a rate of 2° C. per minute until theend-of-melting temperature is reached. During the subsequent cooling ofthe mixture, the heat of crystallization is released at the temperatureat which crystallization begins. The temperature at which the heat ofcrystallization begins to be released is referred to hereinafter as thebeginning of crystallization. Mixtures of components a) and b) suitablefor the treatment preparations according to the invention begin tocrystallize at a temperature of 40° C. or higher.

In one preferred embodiment, the active-substance mixtures contain afatty component a) containing fatty acid monoglyceride and diglyceride,preferably fatty acid monoglycerides. The fatty acid component of thesemonoglycerides and diglycerides is derived from linear or branched fattyacids which may be saturated or unsaturated and which contain from 10 to24 carbon atoms. A typical example of suitable glyceride mixtures is,for example, a mixture consisting of fatty acid mono and diglycerideswhich mainly contains fatty acid monoglyceride and of which the fattyacid component is derived from stearic acid. A glycerolmono-/dipalmitate/stearate containing 40 to 60% monoglyceride is alsosuitable.

A preferred embodiment of the preparation according to the inventioncontains fatty acids having a melting point in the range from 40° C. to80° C. and preferably in the range from 45° C. to 65° C. in the fattycomponent a). The fatty acids may be of natural and synthetic origin andare generally linear and, in particular, saturated. Natural fatty acidsare derived from triglycerides, for example from coconut oil, palmkernel oil, olive oil, or even from animal fats, such as beef tallow,fish oil or lard. Commensurate with their provenance, the fatty acidsderived therefrom are mixtures of different fatty acids and are alsopreferred if they have a melting point, optionally after hydrogenation,in the range from 40° C. to 80° C. and more particularly in the rangefrom 45° C. to 65° C.

In addition to the fatty acid glycerides or fatty acids alreadymentioned, the fatty component a) may also contain fatty alcohols.Preferred fatty alcohols for the preparations according to the inventioncontain 10 to 22 carbon atoms in the molecule. The provenance of thefatty alcohols may be the same as mentioned above for the fatty acids.In other words, the fatty alcohols may also be of synthetic or naturalorigin and, optionally after hydrogenation, may be mixtures of differentfatty alcohols. Fatty alcohols containing 10 to 22 carbon atoms arepreferred.

The fatty alcohol alkoxylates suitable for component b) are generallybased on the fatty alcohols also suitable for the fatty component a).They contain 1 to 15 moles of ethylene oxide and/or 1 to 15 moles ofpropylene oxide per mole of fatty alcohol. Fatty alcohol alkoxylates, inwhich ethylene oxide and propylene oxide are simultaneously added ontothe fatty alcohol, are preferred. More particularly, suitable fattyalcohol alkoxylates contain 2 to 8 moles of ethylene oxide and/orpropylene oxide per mole of fatty alcohol.

In addition to fatty alcohol alkoxylates, component b) may contain fattyacid esters of monohydric alcohols. Preferred fatty acid esters ofmonohydric alcohols contain a total of 15 to 44 carbon atoms. Suitablemonohydric alcohol components are, in particular, methyl alcohol, ethylalcohol, n-propyl alcohol and isopropyl alcohol. The foregoingobservations in respect of the fatty acids also apply to the fatty acidcomponent of suitable fatty acid esters of monohydric alcohols. In thecontext of the invention, fatty acid esters of monohydric alcohols arealso understood to include fatty acid ester mixtures of differentcomposition, including for example the carnauba wax obtainable from theleaves of the Brazilian fan palm Copernica prunivera, the candelilla waxobtained from the leaves of Euphorbiaceae, jojoba oil and natural orsynthetic beeswax. A suitable synthetic beeswax is, for example, amixture containing 40 parts by weight of a fatty acid monoglyceride, ofwhich the acid component is a 3:1 mixture of hydroxystearic acid andhydrogenated castor oil, 35 parts by weight of palmitic acid cetylester, 20 parts by weight of microwax, 10 parts by weight ofhydroxystearic acid and other constituents in small quantities. Naturalester mixtures such as these are also regarded as fatty acid esters ofmonohydric alcohols in the context of the present invention.

To ensure that they have the preferred beginning of crystallization at atemperature of 40° C. or higher, the active-substance mixtures consistof component a) and component b) in a ratio by weight of 3:1 to 1:3 andpreferably in a ratio by weight of 2:1 to 1:2. Preparations according tothe invention in which the mixtures contain component a) and componentb) in the ratio by weight mentioned are preferred. Occasionally, it canbe useful to modify the beginning of crystallization by additions oforganic solvents. The addition of an effective quantity of glycerol,generally amounting to between 1 and 15% by weight, based on theactive-substance mixtures, is particularly suitable for this purpose.

Although, in principle, the flexible sheet-form material used as carrierfor the mixture of active substances may contain a sufficient quantityof the mixtures for one application or even for several applications,the preparations preferably contain a quantity of component a)+b)sufficient for one application. This quantity is preferably 1 to 5 g andis applied to one or both sides of the flexible sheet-form material.

For application to the flexible sheet-form material, the mixtures ofactive substances are liquefied by heating. Particularly suitablemixtures have a viscosity at 60° C. of 5 to 100 mPas and are thereforepreferred.

By virtue of the fact that the constituents of the active-substancemixtures of the preparations according to the invention do not containsignificant amounts of flammable liquids by virtue of their originationfrom natural and renewable raw materials, the flash point of themixtures is distinctly higher than that of the mixtures generally usedfor the known preparations for the treatment of washed laundry in atumble dryer. This is another advantage of the preparations according tothe invention. Accordingly, preparations according to the invention ofwhich the active-substance mixtures have a flashpoint above 55° C. andpreferably above 100° C. are particularly preferred. A flashpoint ashigh as this has a particularly favorable effect in the production ofthe preparations according to the invention where the mixtures of activesubstances are applied to the flexible sheet-form material at elevatedtemperature.

The flexible sheet-form material used for the preparations according tothe invention may be a fibrous sheet-form material and, accordingly, maybe a woven or knitted textile material or even a nonwoven material.Foam-like or sponge-like materials of natural or synthetic origin, suchas for example foamed synthetic polymers preferably present in sheetform, are also suitable as the flexible sheet-form materials. Theflexible sheet-form materials generally have a lower adsorption capacitythan the foam-like or sponge-like materials. The lower adsorptioncapacity is usually associated with a high release rate of theactive-substance mixtures whereas the foam-like or sponge-likematerials, although capable of absorbing more active-substance mixture,generally do not release it as completely in the tumble dryer. Textileflexible sheet-form materials above all and especially nonwovens haveproved to be particularly successful. Compared with the sponge-like orfoam-like materials, they have a low to medium adsorption capacity andare preferred for the preparations according to the invention. Flexiblesheet-form materials in the form of a nonwoven of synthetic and naturalfibers are particularly preferred carriers for the active-substancemixtures.

Although the preparations according to the invention do not contain anysalt-like constituents, such as quaternary ammonium salts for example,in their active-substance mixtures, the fabrics treated with thepreparations according to the invention show surprisingly goodanti-electrostatic properties after treatment in a tumble dryer attemperatures in the range from about 50° to 80° C. In addition, thepreparations according to the invention are convincing in the sum totalof the desirable properties present. They are easy to produce, do nothave an unpleasant feel after their production, are capable of almostcompletely releasing the mixtures of active substances and transferringthem to the fabrics to be treated in the tumble dryer and provide thefabrics to be treated with a pleasant soft and full feel and withexcellent anti-electrostatic properties. Since in addition the mixturesof active substances are free from quaternary ammonium compounds,environmental pollution by the active substances entering the receivingwaters with the washing water of the washing process following thetreatment in the tumble dryer is minimal in the extreme. Anotheradvantage of the preparations according to the invention lies in thefact that the components present in the active-substance mixtures aremade from natural and renewable raw materials.

In addition to the constituents mentioned in the foregoing, the mixturesof active substances may also contain auxiliaries and additives typicalof preparations for the treatment of washed laundry in a tumble dryer,including for example fragrances, dyes, heavy metal complexing agents,clay materials or fine-particle silica.

EXAMPLES

Quantities of 3 g of active-substance mixtures having the following twocompositions A and B were uniformly applied to 14 cm×25 cm pieces of arandom-fiber nonwoven consisting of polyester and cellulose fibers("Keybak 02", a product of Chicopee, Netherlands).

    ______________________________________                                        Composition (%)        A     B                                                ______________________________________                                        Glycerol monostearate  47    47                                               containing 60% monoglyceride                                                  C.sub.10/14 -fatty alcohol                                                                           41    --                                               + 1.2 moles of propylene oxide                                                + 6.4 moles of ethylene oxide                                                 Isopropyl stearate     --    46                                               Beeswax substitute     5     --                                               Perfume oil             7     7                                               ______________________________________                                    

The beginning of crystallization was at 42° C. for mixture A and at 46°C. for mixture B. For commercial 75% by weight distearyl dimethylammonium chloride (DSDMAC) containing the same quantity of perfume oil,the beginning of crystallization was at 27° C.

The flashpoint was 166° C. for mixture A, 156° C. for mixture B and 28°C. for the DSDMAC mixture. Accordingly, the DSDMAC mixture has to behandled as a hazardous material whereas mixtures A and B of thepreparations according to the invention do not. In every case,correspondingly treated fabrics had substantially the same soft feel.

The anti-electrostatic properties, measured as the dissipation half-timeof an applied electrical charge, amounted to 7.6 seconds (A), 10.6seconds (B) and 36 seconds (DSDMAC).

In every case, the release of active substance was substantiallycomplete (>96% release rate).

Despite the use of a carrier material having the relatively lowadsorption capacity of around 6,as measured by the method described inU.S. Federal Specification UU-T-595 b and modified in accordance withDE-A 27 00 512, the treated textiles did not show any stains.

The toxicological, ecological and ecotoxicological behavior of mixturesA and B was better in every respect than that of DSDMAC.

We claim:
 1. An article for the treatment of washed laundry in a tumbledryer, said article comprising a fibrous flexible sheet-form substratecoated with a mixture of (a) a fatty component selected from the groupconsisting of a fatty acid mono-, di-, and tri-glyceride, a fatty acidand a fatty alcohol, and (b) a fatty acid ester of a monohydric alcohol.2. An article according to claim 1 wherein said mixture of component (a)and component (b) has a crystallization temperature of 40° C. or higher.3. An article according to claim 1 wherein said fatty component (a)consists essentially of fatty acid monoglyceride and diglyceride.
 4. Anarticle according to claim 1 wherein said fatty component (a) containsfatty acids having a melting point of from 40° C. to 80° C.
 5. Anarticle according to claim 1 wherein said fatty component (a) containsC₁₀ -C₂₂ fatty alcohols.
 6. An article according to claim 1 wherein saidfatty acid ester of a monohydric alcohol contains a total of 15 to 44carbon atoms.
 7. An article according to claim 1 wherein said component(a) and said component (b) are present in a weight ratio of 3:1 to 1:3.8. An article according to claim 1 wherein said substrate contains from1 to 5 grams of said mixture of component (a) and component (b).
 9. Anarticle according to claim 1 wherein said mixture of component (a) andcomponent (b) has a viscosity of from 5 to 100 mPas at 60° C.
 10. Anarticle according to claim 1 wherein said mixture of component (a) andcomponent (b) has a flash point above 55° C.
 11. An article according toclaim 1 wherein said substrate is selected from the group consisting ofa woven or knitted textile material, and a nonwoven synthetic or naturalfiber material.
 12. An article for the treatment of washed laundry in atumble dryer, said article comprising a fibrous flexible sheet-formsubstrate coated with a mixture of (a) a fatty component selected fromthe group consisting of a fatty acid mono-, di-, and tri-glyceride, afatty acid and a fatty alcohol, and (b) a fatty acid ester of amonohydric alcohol, wherein said mixture of component (a) and component(b) has a crystallization temperature of 40° C. or higher.
 13. Anarticle according to claim 12 wherein said component (a) and saidcomponent (b) are present in a weight ratio of 3:1 to 1:3.
 14. Anarticle according to claim 12 wherein said substrate contains from 1 to5 grams of said mixture of component (a) and component (b).
 15. Anarticle according to claim 12 wherein said substrate is selected fromthe group consisting of a woven or knitted textile material, and anonwoven synthetic or natural fiber material.